s3m2nsf converts s3m files made with a special samplepack to nsf. so, it's a way to make nsf files in your favorite s3m-compatible tracker.
s3m2nsf supports the VRC6 expansion chip (it's enabled if the VRC6 samples are present)
download here (comes with samplepack and documentation):
s3m2nsf automatically converts samples at the end into DPCM, so you might need this tool to convert .dmc samplepacks to raw samples: